I hate to point out the obvious, but for people who don't click the link: that bug was filed in irony (and by somebody who didn't "get" the home lens as a global search tool, but that perceptual problem is ours more than it is anybody else's). The global search functionality could be queried from the commandline (by writing a tool that talked to the backends over dbus, as the dash does), and I half expect somebody to implement a kludgy version of "grep" that did exactly that, it is in no way something we're going to ever ship.
"Desktop" users, of the kind that Ubuntu wants to adopt, aren't going to be using find and grep.